Improvement in devices for crushing and pulverizing clay



`o'f heavy Cast-iron rollers.

UNITED STATEs PATENT WILLIAM L. GREGG, OE CHICAGO, ILLIANOIS.

Specification forming part of Letters Patent No. 156,565, dated November 3, 1874; application filed July 8, 1874.

` To all whom fit may concerw:

lowing is a specification:

The object of my invention is to provide improved means for crushing and disintegrating the clay supplied to the inolds in the manufacture of bricks, and for expelling therefrom stones and other foreign matters detrimental to such manufacture, as well as for thoroughly pulverizing such small pebbles as may happen to pass in with the clay; to which end my improvement consists in the coinbination of conical rollers, to which the clay is first fed, with cylindrical rollers, which perfect and complete the disintegratin g operation commenced by the conical rollers, as hereinafter more fully set forth.

In the manufacture of bricks by machineryan industry which has now become of very considerable importance, both in this country and in Europe-it has been the custom to crush the clay by means of a single pair My father, Isaac Gregg, senior, now deceased, devised and patented the application and use of conical rollers for this purpose instead of the cylindrical rollers theretofore employed, to the end that the larger stones might be caused, by centrifugal force, to ascend to thelarger ends of the rollers, and there be thrown off; and it has been found in practice that thisobject is, generally speaking, satisfactorily attained. I have, however, discovered, by practical experience. in

the manufacture of bricks, that some of the.

smaller stones will, from time to time, pass between the rollers without and that injury to the structure and beauty of the bricks results therefrom, more especially when such pebbles are composed of limestone. Moreover, when the clay is of a very plastic nature, upon leaving the conical rollers, it tends to shoot out into strips or bands, in the manner of putty, and is difficult, if not impossible, to feed into the molds of niachines.

By the use of my improvement the partivsuitable bearings,

being pulverized,

cles of pebbles which are cracked and partially reduced by the conical rollers are thoroughly pulverized and disseminated through.

A substantial frame, A, serves to support and maintain the mechanism in position. In the upper portion of this frame I mount, in a pair of rollers, B B', which are' in the form of frustums of cones, their axes being inclined with reference to each other, and set at such distance apart as is proper to crush the clay, which can'l be fed to them through a hopper, or from an elevator, in any convenient manner. Below these rollers I mount a pair of cylindrical rollers, O 0', in bearings upon the frame.

The two'sets of rollers can be set at such distances apart as' is deemed most convenient; and the lower rollers C O' should be placed sufficiently above the bottom to allow of the convenient removal of the crushed clay to the molds.

The rollers may be driven by belts of gearing, according to the preference of the constructer; and the respective rollers of each pair should travel at different rates of speed, so as to exerta rubbing as well as a grinding action upon the clay.

'In practice I have found the following respective rates of speed to be desirable, to wit, from one hundred to two hundred revolutions per minute for one roller, and from two to three hundred revolutions for the other.

Iam aware that conical rollers have been heretofore known and used, and do not, therefore, broadly claim such device.

I claim as my invention and desire to secure by Letters Patent The combination, in a clay-disintegrating FFICE;

The

mill, of a pair of conical rollers situated pebbles are ground and the elay pulverized, over a pair of cylindrieal rollers, the respeetsubstantially a-s described. ive rollers of each pair moving a-t difl'erent rates of speed, so that the clay shall be fed WM. L. GREGG. first to the conical rollers to remove the Witnes'ses: larger Stones from the elay,wl1ieh thence falls J. W. HARBACH,l

` upon the oylindrical rollers,where the Smaller WM. R. PAGE. 

